Identifying effective PHQ-9 cut-off points for depression in adolescents

PURPOSE: The purpose of this evidence-based practice project was to identify an optimal PHQ-9 Depression screening tool cut-off point in identifying depression in the adolescent population in a primary care setting.
METHODS: A plan-do-study-act model was utilized for the implementation of this project. A retrospective chart review was conducted including statistical analysis and interpretation of the PHQ-9 cut-off points in a primary care practice. A matched pairs t-test was used to analyze the practice-wide use of the PHQ-9 Depression Screening tool in the adolescent population.
RESULTS: Archival data for 90 adolescents was collected. The mean age of participants was 14.97 years. Participants were predominantly Caucasian and female. Thirty-seven (41.1%) of the adolescents were diagnosed with depression based on a mean score of 12.57 on the PHQ-9. Adolescents meeting the criteria for depression had statistically significant higher PHQ-9 scores than those having no diagnosis of depression. The average or mean score for adolescents diagnosed with depression using the PHQ-9 screening tool was 12.57, however, the analysis demonstrated that a score as low as 7.5 could indicate depression. Therefore, a score of > 7.5 was determined to be the optimal cutoff point for maximizing sensitivity of the PHQ-9 without loss of specificity. CONCLUSIONS: The volume of adolescents seen in the primary care setting affords a rich opportunity in identifying depression in the adolescent population. Current evaluation suggests that using the validated PHQ-9 depression-screening tool with cut-off points of 7.50 or greater would be more effective in the current primary care setting, allowing for purposeful interventions to improve screening for depression in the adolescent population and their outcomes.